1. Field of the Invention
The present invention relates to an information receiving system for descrambling scrambled information and presenting the descrambled information.
2. Description of the Related Art
A satellite broadcasting system, which uses a satellite, a CATV (cable television) system, which uses a cable, and so forth have been commercially used as well as the conventional TV (television) broadcasting system, which uses a ground wave. The CATV system provides each subscriber with a subscriber terminal unit. For each subscriber terminal unit, descrambling control, charging process, and so forth are performed.
At present, many families have two or more TV receivers. The users often want to see CATV programs with any TV receiver in their houses. There are several methods to satisfy such needs. FIG. 1 shows one method where a TV signal received from a CATV center is distributed to two subscriber terminal units with a distributor so as to allow the users to see CATV programs with two TV receivers. FIG. 2 shows another method where an RF output terminal of a subscriber terminal unit A is connected to an input terminal of a subscriber terminal unit B so as to receive TV signals transmitted from a CATV center with the two subscriber terminal units.
However, in the above-mentioned methods, the number of subscriber terminal units required must be the same as the number of TV receivers that receive CATV programs or the like. In addition, a number of subscriber contracts are required corresponding to the number of the TV receivers. Even if the contract fee is discounted after the second TV receiver, the users would have to spend a large amount of money. In addition, since the CATV center controls each of subscriber terminal units by transmitting signals with an address number assigned to each of subscriber terminal units. Thus, as the number of subscriber terminal units increases, the processing time of the computer in the CATV center increases.
When a subscriber terminal unit is installed corresponding to each TV receiver, if a user who sees a pay channel program with a TV receiver A, which is connected to a subscriber terminal unit A (see FIG. 1), wants to see the same pay channel program with another TV receiver B in another room, he or she should operate the subscriber terminal unit B connected to the TV receiver B so as to descramble the received signals. In this case, since the CATV center cannot determine whether the same user sees the same pay channel program or another user sees the same pay channel program, it charges for each subscriber terminal unit. Thus, even if the same user continuously sees the same pay channel program with different TV receivers in the same house, the user will be doubly charged for the pay channel program.
An object of the present invention is to provide an information receiving system having a plurality of subscriber terminal units, all of which is not required to have a descrambling function but each of which can reproduce scrambled information.
Another object of the present invention is to provide an information receiving system for allowing the number of subscriber terminal units controlled by a center to be decreased, thereby reducing the load of the processing performed by the center.
A further object of the present invention is to provide an information receiving system for allowing the user to see pay channel programs with a plurality of TV receivers or the like in the house of the subscriber at a moderate cost.
In an information receiving system for descrambling scrambled information and presenting the descrambled information, a parent subscriber terminal unit according to the present invention comprises a descrambling unit for descrambling scrambled information, and an information output unit for outputting the descrambled information received from the descrambling unit to a parent unit side information presenting unit or a child subscriber terminal unit. Information output from the information output unit comprises image information, sound information, and so forth. A child subscriber terminal unit according to the present invention comprises a receiving unit for receiving the descrambled information from the parent subscriber terminal unit. Information received by the receiving unit is output to a child unit side information presenting unit and presented through images, sound, and so forth.
An information receiving system according to the present invention is, for example, an image information receiving system constructed of a center for transmitting information and a plurality of subscriber terminal units. The parent subscriber terminal unit further comprises a channel signal receiving unit for receiving a channel command signal that represents a desired receive channel of the child subscriber terminal unit, a control unit for controlling the switching of the descrambled information descrambled by the descrambling unit to the child terminal unit or to the parent unit side information presenting unit based on the channel command signal of the child subscriber terminal unit received from the channel signal receiving unit and the desired receive channel of the parent subscriber terminal unit, and a parent unit side information presenting unit for presenting descrambled information descrambled by the descrambling unit through images, sound, and so forth. The child subscriber terminal unit further comprises a channel signal output unit for outputting a channel command signal that represents a desired receive channel of the child unit side information presenting unit to the parent subscriber terminal unit and a child unit side information presenting unit for presenting descrambled information descrambled by the parent subscriber terminal unit through images, sound, and so forth.
These and other objects, features and advantages of the present invention will become more apparent in light of the following detailed description of a best mode embodiment thereof, as illustrated in the accompanying drawings.